Rotational driving mechanism in a robot
A rotational driving mechanism for driving a first member and a second member, which are part of a robot, to rotate relatively on a predetermined rotational driving plane by means of a linear motion actuator having a linear motion output shaft, includes: a first link unit with which the output shaft is connected, and which is arranged so as to be rotatable with respect to the first member through a first rotation shaft, and which is also arranged so as to be rotatable with respect to the second member side through a second rotation shaft; a second link unit which is connected with a first support shaft arranged at the first member side, and which is connected with a second support shaft arranged at the second member side, with a center distance between the first support shaft and the second support shaft being made constant.
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The present invention relates to a rotational driving mechanism for rotationally driving members, which are part of a robot, relative to each other.
BACKGROUND ARTIn recent years, there have been actively made research and development of not only industrial robots but also consumer robots, which play various roles for people's livelihood. Among such robots, human-like robots (humanoid robot) being able to walk in erect posture are expected to be able to substitute for actions of human beings. In such humanoid robots, many joint parts are provided for imitating actions or motions of a human being, and a variety of motions having a plurality of degrees of freedom in the joint parts are required.
For example, in FIG. 6 of patent literature 1, there is disclosed a joint structure of a leg unit of a robot. Specifically, a thigh part located at an upper side of the leg unit and a crus part located at a lower side of the leg unit are connected with a plate member so as to be rotatable relative thereto. Then, these parts and member are arranged in such a manner that when the leg unit becomes the most extended state, the plate member abuts against a stopper at the side of the thigh part and a stopper at the side of the crus part. With such an arrangement, when the robot extends its leg units and stands erect, each stopper and the plate member become an abutted state due to the self weight of the robot, so it becomes possible to maintain the erect state of the robot in a relatively stable manner. In addition, in order to maintain the contact state of the stoppers and the plate member at the time of the erect standing of the robot, an arrangement is also adopted in which springs are provided at the thigh part side and at the crus part side, respectively, to apply resilient forces.
CITATION LIST Patent Literature[Patent Literature 1] International laid-open publication No. 2013/084789
SUMMARY OF THE INVENTION Technical ProblemIn a construction in which a plurality of members are rotatably connected with each other at a joint part, as in a leg unit, an arm unit, etc., which are part of the robot, (hereinafter, referred to as a “robot construction unit”), in order to expand the movable range of the robot as much as possible and to improve the versatility thereof, too, it is preferable that the rotation range of the members in each joint part be as wide as possible. However, in general, in the interior of each of the members which form the robot construction unit, a large number of electrical components, such as actuators for driving each joint part, power cables, signal cables, etc., in addition to a skeletal structure for strengthening rigidity are accommodated, and each member is also a structural body having a fixed size.
For that reason, when the individual members of the robot construction unit are driven to rotate with respect to each other, the movable range of each member will be decided within a range in which the outside surfaces of the individual members defined by the sizes thereof do not contact and interfere with each other, and it is difficult to make the movable range relatively wide. On the other hand, in order to avoid the interference between the individual members of the robot construction unit, it is necessary to provide a predetermined deformation to each of the members by scooping their outside surfaces, etc., at a location at which they interfere with each other, but in that case, the skeletal structure inside each member, the arrangement of electrical components therein, etc., must be changed, so that the degree of design freedom of the robot is reduced to a large extent.
The present invention has been made in view of the problems as mentioned above, and has for its object to provide a rotational driving mechanism in a robot which is arranged between two members to be driven to rotate relative to each other, and in which a rotation range between both the members can be made as wide as possible, without adding a large change to the shapes of the outer surfaces of both the members.
Solution to ProblemIn the present invention, in order to solve the above-mentioned problems, there is adopted a construction which corresponds to a joint part between a first member and a second member performing a relative rotational movement, and which serves to associate the first member and the second member with each other by means of a first link unit with which the first member and the second member are respectively connected in such a manner as to be rotatable, and a second link unit by which a center distance between a first support shaft at the side of the first member and a second support shaft at the side of the second member is made constant. With this, a space for rotational driving can be obtained between the first member and the second member, thus making it possible to avoid interference of both the members.
Specifically, a rotational driving mechanism according to the present invention is a rotational driving mechanism for driving a first member and a second member, which are part of a robot, to rotate relatively on a predetermined rotational driving plane by means of a linear motion actuator having an output shaft that moves linearly, the rotational driving mechanism comprising: a first link unit with which an output shaft of the linear motion actuator is connected, and which is arranged so as to be rotatable with respect to the first member through a first rotation shaft, and which is also arranged so as to be rotatable with respect to the second member side through a second rotation shaft, with a center distance between the first rotation shaft and the second rotation shaft being set to a predetermined distance which enables rotational driving of the first member and the second member on the predetermined rotational driving plane; and a second link unit which is connected with a first support shaft arranged at the first member side, and which is connected with a second support shaft arranged at the second member side, with a center distance between the first support shaft and the second support shaft being made constant. Further, the first support shaft and the second support shaft are arranged with respect to the first rotation shaft and the second rotation shaft in such a manner that a straight line connecting the first support shaft and the second support shaft intersects a straight line connecting the first rotation shaft and the second rotation shaft on the predetermined rotational driving plane.
The rotational driving mechanism according to the present invention is a mechanism for achieving relative rotational driving between the first member and the second member, and is provided with the first link unit and the second link unit. The first link unit is a link member with which the first member and the second member are connected through the first rotation shaft and the second rotation shaft, respectively, so as to be rotatable. Accordingly, although the first member and the second member are driven to rotate relative to each other, these members are not directly connected with each other so as to be mutually rotatable, but they are connected with each other through the first link unit so that they become rotatable on the different rotation shafts, respectively. The plane of rotation of each of these members corresponds to the predetermined rotational driving plane. For that reason, between the first member rotating around the first rotation shaft and the second member rotating around the second rotation shaft, there is formed a separate space corresponding to the predetermined distance which is the center distance between both the rotation shafts, and hence, due to the existence of the separate space, the first member and the second member become difficult to interfere with each other in the rotational driving on the predetermined rotational driving plane. With this, it becomes possible to achieve relative rotational driving between the first member and the second member in a wider range.
On the other hand, by connecting the first member and the second member with each other by means of the first rotation shaft and the second rotation shaft, respectively, both the members become a state where they are structurally independent from each other in the relative rotational driving between the first member and the second member. Accordingly, both the members are connected with each other through the second link unit. Specifically, the second link unit is connected with both the first and second support shafts so that the center distance between the first support shaft arranged at the first member side and the second support shaft arranged at the second member side becomes constant, as mentioned above. Then, these four shafts are arranged in such a manner that the straight line connecting the first support shaft and the second support shaft intersects the straight line connecting the first rotation shaft and the second rotation shaft, on the predetermined rotational driving plane. With this arrangement, the relative rotational driving of the first member and the second member becomes possible in a state where the distance between the first support shaft and the second support shaft has been made constant by the second link unit.
As described above, when an output from the linear motion actuator is applied to the rotational driving mechanism according to the present invention, for example, the first member is driven to rotate around the first rotation shaft with respect to the first link unit. At this time, because the first member is connected with the second member through the second link unit, the second member will be driven to rotate around the second rotation shaft with respect to the first link unit, in conjunction with the rotation of the first member, thereby making it possible to achieve relative rotational driving between the first member and the second member. According to such a rotational driving mechanism of the present invention, the relative rotational driving of the first member and the second member, which are connected with each other through the two different rotation shafts, can be achieved by the single linear motion actuator, as a consequence of which the volume of the space required to arrange the actuator can be made small, and the interference of both the members can be avoided as much as possible. As a result, it becomes possible to make the rotation range between the first member and the second member as wide as possible, without adding a large change to the shapes of the outer surfaces of both the members.
Advantageous Effects of InventionIt is possible to provide a rotational driving mechanism in a robot, which is arranged between two members to be driven to rotate relative to each other, and in which a rotation range between both the members can be made as wide as possible, without adding a large change to the shapes of the outer surfaces of both the members.
Hereinafter, specific modes or embodiments of the present invention will be described based on the attached drawings. However, the dimensions, materials, shapes, relative arrangements and so on of component parts described in the embodiments are not intended to limit the technical scope of the present invention to these alone in particular as long as there are no specific statements.
Embodiment 1<Construction of Robot 10>
Reference will be made to the overall construction of a robot 10 on which rotational driving mechanisms according to the present invention are mounted, based on
The robot 10 is a humanoid robot and has a body which imitates a skeletal structure of a human being. Schematically, the skeletal structure of an upper half body of the robot 10 (hereinafter, referred to simply as an “upper half body skeletal structure”) is formed by: a backbone part 14 extending in a z axis direction in
In addition, in the robot 10, driving units 20 for managing the drive of the upper half of the body are arranged corresponding to an upper right half body and an upper left half body, respectively. Here, as shown in
In
<Construction of Arm Unit 50>
Here, the construction of the arm unit 50 will be explained based on
The first arm member 51 has a pair of plate-shaped frames 51a extending along a longitudinal direction thereof and a base frame 51b to which the pair of plate-shaped frames 51a are connected. In addition, with respect to the second arm member 52, too, it similarly has a pair of plate-shaped frames 52a extending along a longitudinal direction thereof and a base frame 52b to which the pair of plate-shaped frames 52a are connected. Here, the distance between the plate-shaped frames 52a at the side of the second arm member 52 is set to be substantially the same as the distance between the plate-shaped frames 51a at the side of the first arm member 51. Then, an opening side in the longitudinal direction of the pair of plate-shaped frames 51a and an opening side in the longitudinal direction of the pair of plate-shaped frames 52a are arranged so as to oppose to each other. Thus, there is formed a space substantially surrounded by the pair of plate-shaped frames 51a, 52a and the base frames 51b, 52b, and in this surrounded space, there are accommodated an actuator 57 for driving to rotate the elbow joint part 54 and a linkage mechanism for the elbow joint part 54 corresponding to a rotational driving mechanism of the present invention, for transmitting an output of the actuator 57 to each arm member.
First, the actuator 57 will be explained. The actuator 57 is a linear motion actuator which has a servo-motor, a main body, and an output shaft 57a performing linear movement in the axial direction of the actuator. The output shaft 57a has a spiral thread groove formed on the outer peripheral surface thereof, and a ball screw nut (not shown) threadedly engaged with the thread groove of the output shaft 57a is received in the main body in such a state that only rotation thereof around an axis line of the main body is permitted. Then, the servo-motor is connected with the main body so as to drive the ball screw nut to rotate, and the movement in the axial direction of the ball screw nut is limited inside the main body, so the output shaft 57a is caused to perform linear motion in the axial direction, i.e., move linearly, by the drive of the servo-motor.
Then, the output shaft 57a of the actuator 57 is connected to the first link unit 53 among the first link unit 53 and the second link unit 55 which together constitute the elbow joint part 54. In addition, the first link unit 53 has two wall portions 53a extended in the same direction from the opposite ends of the base portion 53c, as shown in
In addition, the output shaft 57b of the actuator 57 is connected to the bridge 53b in such a manner that the direction thereof with respect to the first link unit 53 becomes variable, wherein a connection point between the actuator output shaft and the bridge is denoted by 57b (refer to
The first link unit 53 constructed in this manner forms a biaxial joint which connects the first arm member 51 and the second arm member 52 with each other through the first rotation shaft 61 and the second rotation shaft 62, respectively, so as to be rotatable. At this time, the first rotation shaft 61 and the second rotation shaft 62 are separated from each other by a predetermined distance, so the first arm member 51 and the second arm member 52 being rotatable around their rotation shafts, respectively, are placed in a situation where they do not interfere with each other easily. However, the output shaft 57a of the actuator 57 is connected only to the side of the first link unit 53, and hence, the arrangement is not such that the output of the actuator 57 is directly transmitted to the second arm member 62. Accordingly, provision is made for the second link unit 55 which connects the first arm member 51 and the second arm member 52 with each other.
The second link unit 55 is one of link units which form the elbow joint part 54, as mentioned above. Specifically, the second link unit 55 is connected with a first support shaft 63 arranged so as to join between the pair of plate-shaped frames 51a of the first arm member 51, and a second support shaft 64 arranged so as to join between the pair of plate-shaped frames 52a of the second arm member 52. Here, the first support shaft 63 and the second support shaft 64 are arranged with respect to the first rotation shaft 61 and the second rotation shaft 62 in such a manner that a straight line connecting the first support shaft 63 and the second support shaft 64 on a rotational driving plane intersects a straight line connecting the first rotation shaft 61 and the second rotation shaft 62, and at the same time, the first support shaft 63 and the second support shaft 64 are made mutually parallel to the first rotation shaft 61 and the second rotation shaft 62, respectively. As a result of this, rotational driving of the first arm member 51, the second arm member 52, the first link unit 53 and the second link unit 55 by means of the actuator 57, to be described later, will be carried out on the same rotational driving plane. Then, the second link unit 55 maintains the center distance between both the support shafts at a fixed distance by connecting the first support shaft 63 and the second support shaft 64 by means of the link body thereof. By such a construction, it is possible to form correlation between the first arm member 51 and the second arm member 53 having their individual rotation shafts, whereby the second arm member 53 can be operatively connected with the output of the actuator 57. Here, note that the second link unit 55 is arranged so as to be sandwiched by the two wall portions 53a of the first link unit 53.
Here, the first support shaft 63 and the second support shaft 64 are each arranged so as to extend over the plate-shaped frames 51a, 52a which are in opposition to each other, as a result of which in a state where the elbow joint part 54 shown in
Further, the second guide through holes 53e are formed in the base portions 53c of the first link unit 53, respectively, and the shape of each second guide through holes 53e is such that when the first link unit 53 rotates around the second rotation shaft 62, it extends along the locus of the second support shaft 64, and the length thereof in the extending direction becomes a second predetermined length. Accordingly, each second guide through hole 53e is a through hole which has a limited length in the direction extending as the locus of the second support shaft 64 at the time of the rotation of the first link unit 53, for example as shown in
Here, the operation of the elbow joint part 54 formed by the first link unit 53 and the second link unit 55 as mentioned above will be explained, based on
In the maximally extended state shown in
In addition, in the state where the first arm member 51 and the second arm member 52 are generally extended (i.e., a state corresponding to a predetermined extended state according to the present invention) including the maximally extended state, the connection point 57b is located, as shown in
From this maximally extended state, the output shaft 57a of the actuator 57 is pushed out or extended to the side of the first link unit 53 by the drive of the actuator 57, and the connection point 57b approaches the broken line in the figure (
Then, when the output shaft 57a of the actuator 57 is further pushed out or extended to the side of the first link unit 53 and the connection point 57b is displaced to the right side of the broken line in this figure (
The elbow joint part 54 of the first arm member 51 and the second arm member 52 constructed in this manner serves to connect the first arm member 51 and the second arm member 52 with the first link unit 53 through the corresponding first rotation shaft 61 and the corresponding second rotation shaft 62, respectively. Then, the center distance between the first rotation shaft 61 and the second rotation shaft 62 is set as the predetermined distance, and so a region in which the rotation ranges of the individual arm members around the individual rotation shafts interfere with each other can be made as small as possible. As a result, a maximum folding angle in the arm unit 50 can be made as small as possible, without adding a large change to the shapes of the outer or external surfaces of the first arm member 51 and the second arm member 52, as shown in
Further, when the movable range of the connection point 57b is set as mentioned above, the connection point 57b and the first support shaft 63 are located in the rotational driving plane at the same side with respect to the straight line connecting the first rotation shaft 61 and the second rotation shaft 62. Here, it is constructed such that when the connection point 57b is displaced from the state shown in
Moreover, in the relative rotational driving of the first arm member 51 and the second arm member 52, in the maximally extended state in which the arm unit 50 is most extended and in the maximally folded state in which the arm unit 50 is most folded, at least any of the first support shaft 63 and the second support shaft 64, to which the second link unit 55 is connected, is in abutment with an end of the corresponding guide through hole. As a result, it becomes possible to easily form stoppers which serve to mechanically limit the range of the relative rotational driving of the first arm member 51 and the second arm member 52, in other words, even with an easy or simple stopper construction, it will become possible to suppress inconveniences in the relative rotational driving of the first arm member 51 and the second arm member 52 such as, for example, rotational collision of the first arm member 51 and the second arm member 52, etc., in an appropriate manner.
<Modification>
Reference will be made to a modification of the elbow joint part 54 based on
Here, this modification is different from the embodiment shown in
From this maximally extended state, by the drive of the actuator 57, its output shaft 57a is drawn into the actuator 57, whereby the first link unit 53 is caused to rotate in the counterclockwise direction, and in accordance therewith, the second arm member 52 is rotated in the counterclockwise direction around the second rotation shaft 62. As a result, eventually, as shown in
Thus, when the movable range of the connection point 57b is set in this manner, the connection point 57b and the first support shaft 63 are located in the rotational driving plane at the opposite sides, respectively, with respect to the straight line connecting the first rotation shaft 61 and the second rotation shaft 62. Here, it is constructed such that when the connection point 57b is displaced from the state shown in
Here, when comparing this modification with the above-mentioned embodiment, in the elbow joint part 54 according to this modification, the second arm member 52 will be folded with respect to the first arm member 51 by drawing in or retracting the output shaft 57a of the actuator 57, but on the other hand, in the elbow joint part 54 according to the above-mentioned embodiment, the second arm member 52 will be folded with respect to the first arm member 51 by pushing out or extending the output shaft 57a of the actuator 57. Thus, the correlation between the direction of linear motion of the output shaft 57a and the folding direction of the elbow joint part 54 is different between this modification and the above-mentioned embodiment, but as the elbow joint part 54 in the robot, it is only necessary to select and apply any of these modes suitably according to various reasons. For example, in cases where preferable friction characteristics are obtained in a specific direction of linear motion of the output shaft 57a in the actuator 57, the elbow joint part 54 with a wide rotational driving range can be formed by deciding, based on the above-mentioned disclosure, an arrangement of the connection point 57b and the first support shaft 63 in the rotational driving plane in that case, after deciding the direction of linear motion of the output shaft in consideration of the friction characteristics.
Embodiment 2Now, reference will be made to a second embodiment of the present invention, based on
In the elbow joint part 54 constructed in this manner, the second link unit 55 as the side plate is connected with the first support shaft 63 and the second support shaft 64, and the first support shaft 63 and the second support shaft 64 are in a state where they are inserted in the guide through holes 53d, 53e (not shown in
In the embodiments thus far described, the elbow joint part 54 in the arm unit 50 has been exemplified as the rotational driving mechanism according to the present invention, but instead of this, the present invention may also be applied to knee joint parts in the leg units of the robot 10, i.e., a knee joint part for driving to rotate a thigh part and a crus part relative to each other, in cases where a leg unit is formed by the thigh part and the crus part. In addition, the present invention can also be applied to other joint parts, i.e., joint parts for connecting those members with each other which construct a robot and which are driven to rotate relative to each other.
REFERENCE SIGNS LIST
- 10 . . . robot,
- 14 . . . backbone part,
- 14a . . . anterior clavicular part,
- 14b . . . posterior clavicular part,
- 14c . . . anterior sternal part,
- 14d . . . posterior sternal part,
- 15 . . . hip bone part,
- 19 . . . spring,
- 20 . . . driving unit
- 50 . . . arm unit,
- 51 . . . first arm member,
- 51c . . . rotation inner side surface,
- 52 . . . second arm member,
- 52c . . . rotation inner side surface,
- 53 . . . first link unit
- 54 . . . elbow joint part,
- 55 . . . second link unit
- 56 . . . rotation shaft,
- 57 . . . actuator,
- 61 . . . first rotation shaft
- 62 . . . second rotation shaft
- 63 . . . first support shaft
- 64 . . . second support shaft
Claims
1. A rotational driving mechanism in a robot, for driving a first member and a second member, which are part of the robot, to rotate relatively on a predetermined rotational driving plane by means of a linear motion actuator having an output shaft that moves linearly, the rotational driving mechanism comprising:
- a first link unit with which an output shaft of the linear motion actuator is connected, and which is arranged so as to be rotatable with respect to the first member through a first rotation shaft, and which is also arranged so as to be rotatable with respect to the second member side through a second rotation shaft, with a center distance between the first rotation shaft and the second rotation shaft being set to a predetermined distance which enables rotational driving of the first member and the second member on the predetermined rotational driving plane; and
- a second link unit which is connected with a first support shaft arranged at the first member side, and which is connected with a second support shaft arranged at the second member side, with a center distance between the first support shaft and the second support shaft being made constant;
- wherein the first support shaft and the second support shaft are arranged with respect to the first rotation shaft and the second rotation shaft in such a manner that a straight line connecting the first support shaft and the second support shaft intersects a straight line connecting the first rotation shaft and the second rotation shaft on the predetermined rotational driving plane, and
- the first link unit further has a guide through hole into which the first support shaft and the second support shaft are inserted in their shaft length directions, respectively, and which has a predetermined length formed in such a manner that the first support shaft and the second support shaft become able to relatively move along the predetermined rotational driving plane, and when an output from the linear motion actuator is applied, the first support shaft and the second support shaft are moved relative to each other by the guide through hole in an extending range of the guide through hole, respectively, whereby a relative rotational driving range of the first member and the second member is decided.
2. The rotational driving mechanism in a robot as set forth in claim 1, wherein
- the movement of the first support shaft or the second support shaft in the guide through hole is prevented by the contact of the first support shaft or the second support shaft with an end of the guide through hole, whereby a maximally folded state is formed in which a rotation inner side surface of the first member and a rotation inner side surface of the second member in the predetermined rotational driving plane comes the closest to each other.
3. The rotational driving mechanism in a robot as set forth in claim 1, wherein
- the movement of the first support shaft or the second support shaft in the guide through hole is prevented by the contact of the first support shaft or the second support shaft with an end of the guide through hole, whereby a maximally extended state is formed in which a shaft center of the first member and a shaft center of the second member in the predetermined rotational driving plane are positioned on the same straight line.
4. The rotational driving mechanism in a robot as set forth in claim 1, wherein
- in the predetermined rotational driving plane, a connection point between the output shaft of the linear motion actuator and the first link unit is displaced in a movable range extending across the first rotation shaft along an extending direction of the output shaft;
- when the first member and the second member are placed in a predetermined extended state, the connection point is located at the first member side in the movable range, and in the predetermined rotational driving surface, the connection point and the first support shaft are constructed in such a manner that they are located at the same side with respect to a straight line connecting the first rotation shaft and the second rotation shaft; and
- by the displacement of the connection point from one end side to the other end side in the movable range, the second member is driven to rotate with respect to the first member.
5. The rotational driving mechanism in a robot as set forth in claim 1, wherein
- in the predetermined rotational driving plane, a connection point between the output shaft of the linear motion actuator and the first link unit is displaced in a movable range extending across the first rotation shaft along an extending direction of the output shaft;
- when the first member and the second member are placed in a predetermined extended state, the connection point is located at the second member side in the movable range, and in the predetermined rotational driving surface, the connection point and the first support shaft are constructed in such a manner that they are located at opposite sides, respectively, across a straight line connecting the first rotation shaft and the second rotation shaft; and
- by the displacement of the connection point from one end side to the other end side in the movable range, the second member is driven to rotate with respect to the first member.
6. The rotational driving mechanism in a robot as set forth in claim 1, wherein
- the first member and the second member are members forming an arm unit of the robot, respectively, and the first link unit and the second link unit form an elbow joint of the arm unit;
- or, the first member and the second member are members forming a leg unit of the robot, respectively, and the first link unit and the second link unit form a knee joint of the leg unit.
7. A rotational driving mechanism in a robot, for driving a first member and a second member, which are part of the robot, to rotate relatively on a predetermined rotational driving plane by means of a linear motion actuator having an output shaft that moves linearly, the rotational driving mechanism comprising:
- a first link unit with which an output shaft of the linear motion actuator is connected, and which is arranged so as to be rotatable with respect to the first member through a first rotation shaft, and which is also arranged so as to be rotatable with respect to the second member side through a second rotation shaft, with a center distance between the first rotation shaft and the second rotation shaft being set to a predetermined distance which enables rotational driving of the first member and the second member on the predetermined rotational driving plane; and
- a second link unit which is connected with a first support shaft arranged at the first member side, and which is connected with a second support shaft arranged at the second member side, with a center distance between the first support shaft and the second support shaft being made constant;
- wherein the first support shaft and the second support shaft are arranged with respect to the first rotation shaft and the second rotation shaft in such a manner that a straight line connecting the first support shaft and the second support shaft intersects a straight line connecting the first rotation shaft and the second rotation shaft on the predetermined rotational driving plane, and
- the second link unit is arranged in a state where it is sandwiched by the first link unit in a width direction of the first link unit.
8. The rotational driving mechanism in a robot as set forth in claim 7, wherein
- the first link unit further has a guide through hole into which the first support shaft and the second support shaft are inserted in their shaft length directions, respectively, and which has a predetermined length formed in such a manner that the first support shaft and the second support shaft become able to relatively move along the predetermined rotational driving plane, and when an output from the linear motion actuator is applied, the first support shaft and the second support shaft are moved relative to each other by the guide through hole in an extending range of the guide through hole, respectively, whereby a relative rotational driving range of the first member and the second member is decided.
9. A rotational driving mechanism in a robot, for driving a first member and a second member, which are part of the robot, to rotate relatively on a predetermined rotational driving plane by means of a linear motion actuator having an output shaft that moves linearly, the rotational driving mechanism comprising:
- a first link unit with which an output shaft of the linear motion actuator is connected, and which is arranged so as to be rotatable with respect to the first member through a first rotation shaft, and which is also arranged so as to be rotatable with respect to the second member side through a second rotation shaft, with a center distance between the first rotation shaft and the second rotation shaft being set to a predetermined distance which enables rotational driving of the first member and the second member on the predetermined rotational driving plane; and
- a second link unit which is connected with a first support shaft arranged at the first member side, and which is connected with a second support shaft arranged at the second member side, with a center distance between the first support shaft and the second support shaft being made constant;
- wherein the first support shaft and the second support shaft are arranged with respect to the first rotation shaft and the second rotation shaft in such a manner that a straight line connecting the first support shaft and the second support shaft intersects a straight line connecting the first rotation shaft and the second rotation shaft on the predetermined rotational driving plane, and
- the second link unit is arranged outside the first link unit in a width direction of the first link unit, and is formed as a side plate which is arranged at a further outer side of an outer surface of the first member and an outer surface of the second member.
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Type: Grant
Filed: Oct 27, 2015
Date of Patent: Mar 3, 2020
Patent Publication Number: 20180290295
Assignee: THK CO., LTD. (Tokyo)
Inventor: Masaki Nagatsuka (Tokyo)
Primary Examiner: Vicky A Johnson
Application Number: 15/522,548
International Classification: B25J 9/10 (20060101); B25J 17/00 (20060101); B25J 18/00 (20060101);